The relatively open and known architecture of a typical hard disk drive (HDD) renders it fairly easy for determined and minimally-funded attackers to duplicate content stored on the HDD. Low-level block copy software is easily available and produces an unauthorized drive image copy of the stored HDD content that is indistinguishable from the authorized source HDD for many host applications. Preventing a determined attacker from copying a drive's image to another drive and then using that copy on another host is difficult. Standard content encryption methods typically disallow viewing of the copied encrypted content, but it does not securely prevent the use of that content on another host having a valid decryption or usage key.
Typically, hardware authorization keys have been used to identify an authorized host. These keys have an added hardware cost and have historically been broken and duplicated in as little as a few days. This approach does not normally differentiate between source and copied contents. Other approaches to protect against unauthorized copying and/or use of disk contents typically require adding hardware to the host and/or disk drive to provide a secured or keyed communication channel and encrypted or keyed contents on the HDD. This approach generally adds hardware cost to the host and/or HDD. Also, this solution is not always transportable across HDD vendors because they can require custom hardware. Moreover, copying encrypted contents to another H-DD does not explicitly prevent its use. Another typical prior approach is requiring the original authorized CD-ROM to be physically present in a CD drive during use of the software or data. However, copying the original CD-ROM is easy. Thus, there is a need for a method to secure specific files to prevent the use of an unauthorized copied file stored on a storage medium.